Properties of the Number 20645

Twenty Thousand Six Hundred Forty-Five

Basics

Value: 20644 → 20645 → 20646

Parity: odd

Prime: No

Previous Prime: 20641

Next Prime: 20663

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 5 × 4129

Divisors: 1, 5, 4129, 20645

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000010100101

Octal: 50245

Duodecimal: BB45

Hexadecimal: 50a5

Square: 426216025

Square Root: 143.68368035375485

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Number G(n,k) of set partitions of {1,...,n} into sets of size at most k; triangle G(n,k), n>=0, 0<=k<=n, read by rows. A229223

Number of separable type set partitions of {1..n}. A386633

Triangle read by rows where T(n,k) is the number of unlabeled connected multigraphs with loops with n edges and k vertices. A322115

The partition function G(n,5). A110038

Sum of the second largest parts of the partitions of n into 8 squarefree parts. A326451

p-INVERT of (1,1,0,0,0,0,...), where p(S) = 1 - S - S³. A291397

Antidiagonal sums of triangle A183202. A183203

Number of partitions of n into parts not of the form 19k, 19k+4 or 19k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 8 are greater than 1. A35973

Positive integers whose square is the sum of 74 consecutive squares. A257825

Least positive integer k for which 4ⁿ divides k!. A20645